Fluid differential



July 31, 1951 R. v'. DE LA HITTE FLUID DIFFERENTIAL Filed June 1, 1949 FIG 2 FIGI-- INVENTHR MM 0 by 54 'ATTORNEY Patented July 31, 1951 FLUID DIFFERENTIAL Rodolphe Valery de la Hitte, Victoria, British Columbia, Canada Application June 1, 1949, Serial No. 96,423

2 Claims. 1

The invention relates to improvements in' a fluid differential, as described in the present specification and illustrated in the accompanying drawings that form a part of the same.

The invention consists essentially of the novel features in construction as pointed out broadly and specifically in the claims following a description containing an explanation in detail of an acceptable form of the invention.

The objects of the invention are to devise a differential the action of which is provided by fluid flow set to produce the correct ratio between tWo driven shafts automatically when required; to make a non-rigid device utilizing fluid as the transmitting medium, incorporating a by-pass action providing a cushioning effect between the transmission and the rear axle when the load is applied; to make a gear'less differential having a minimum or working parts and in which the possibility of mechanical failure is greatly re-*- duced; to construct a fluid differential consisting of comparatively few and simple parts and that tial; and generally to provide afluid differential that is'eflicient in its use.

In the drawings: I

. Figure 1 is a half sectionalplan view of the differential.

Figure 2 is a side view of the differential with one half of the cover removed.

Figure 3 is a fragmentary sectional-view as taken on the line 3-3 in Figure 2.

Figure 4 is a half sectional view showing the porting arrangement.

Figure 5 is a perspective view of one of the vanes. v

Like numerals of-reference indicate corresponding parts in the various figures.

The present invention relates to the substitution of fluid for the ordinary gearing as applied to the principles of a differential for the transmisson of power and can be applied to any case 2 slightly smaller in circumference than the recess, forming a circumferential space or chamber l7 between its edge and the inner wall of the recess. The rotor is positioned in the recess with its inner face abutting the face of the recess. The inner or circumferential side wall ll; of each of the recesses II and I2 is fashioned with an identical cam portion [9.

A plurality of vanes 2-0 are secured to eachof the circular rotors l3 and it, four in each rotor preferably being the minimum number. These vanes are rectangular in shape, having a longitudinal. slot 2| extending its entire length. The

lower end portion of the vane is waisted or reduced, being of lesser width than the upper portion. Notches 22 and 23 are located in the Vane the cut-out extending from the edge of the rotor into the body portion. An elongated recess 25' in the body of the rotor leads from the lower end of the cut-out and provides an enclosure for a' spring 26, the spring contacting the bottom end of the vane and pressing upward thereon. A plate fits into a circular recess 28 in the face of the rotor and is suitably secured, this plate 21 covering'the lower portion of the vane and the spring. Each of the vanes as positoned in the rotor, has its top end abutting the side wall l8 of the recess, the spring forcing the vane upward and holding it under pressure against the side wall of the recess, the vanes as thus positioned blocking off the annular chamber ll at that point. The vanes are preferably assembled in the rotor with the slotted portions facing in pairs, the vanes being equally spaced around the periphery of the rotor.

Each of the flat faces of the differential casing [G has a cover plate, 28 and 29, removably secured thereto, each plate having a boss, 39 and SI, formed integral therewith in which the rotor shafts are rotatably mounted. Each of the bosses is provided with a bearing, 32 and 33 on the outside thereof, these bearings adapting the complete assembly to be rotatably mounted in a suitable housing. The plate with its boss and bearing may be made up as a single member. The plates are secured by means of bolts an and 35 to completely enclose the vaned rotors in their respective recess. A suitable viscous fluid, such as silicon, is placed in the annular chamber H in each of the recesses H and I2 before positioning the covers to the casing, the plates being sealed with any suitable type fluid seal, 3% and 31.

The pair of vaned rotors are identical units. the cam I Q being so shaped that the vanes, when rotating, will be pushed towards the center of the rotor when they come in contact with the central portion of the cam section.

Each side of the casing I is provided with a pair of V-shaped recesses or ports, forming fluid chambers, 33 and 39, and 69 and il respectively, one on each side of the center portion of the cam 19. These ports lead from the side wall I8 of the recess H or I? as the case may be, into the body of the casing, the port tapering down to a point at either extremity of the cam. A metering channel or tube, 52 and 43 respectively, is located between and connects the port 38 with the port 40, the ports 39 and 45 being connected by the metering channel or tube 13. The inner diameter of these metering channels or tubes is determined by the viscosity of the fluid medium used in the differential case. In the case of tubes being used, they can be replaced by similar units with different inner diameters, so as to change, if necessary, the ratio of fluid flow thereby changing the ratio of differential action.

The cover plates 28 and 29 are each provided with circular recesses, in which rubber plugs 44 are mounted, these plugs, when the plates are in position on the casing, fitting to a portion of a port in alignment with the metering channel or tube, as shown in Figure 3. These plugs are used to absorb pulse shock or expansion of fluid during its transfer from one port to another, as will hereinafter be described.

A circular chamber 48 is centrally located in the casing it, being the reservoir containing the main bulk of the fluid used. An inlet 43 extends through the casing to the storage chamber 48 through which the fluid is fed to the chamber, a suitable plug or bolt being fitted thereto. The rotor shafts or axles extend through the rotors to project beyond their inner face, these projections or shaft ends 5| and 52 extending into the main storage chamber MB. A plurality of holes are located radially around the shaft end 5!, these holes 53 being communicating apertures between the storage chamber 48, and the recess or chamber of the rotor I3. municating holes 5 are repeated through to the other rotor recess. The fluid feeds from the main storage chamber 48 through these connecting holes to enter the. rotor chambers or recesses by reason of the allowance made in the flt of the rotors within the chambers.

A gear 55, cast integrally with the differential casing It, or suitably attached thereto, is designed for the transmission of power from a power source to activate the casing ID, rotating it in its housing.

In the present instance, the fluid differential is used in connection with a. motor vehicle, or other power vehicle.

In the operation of the fluid differential, power applied to the casing it! is distributed proper: tionately to the two vaned rotors l3 and I l enclosed in the casing, and to the axle shafts l5 and it connected thereto.

By reason of the disposition of the similar cams IS in juxtaposition with their metering channels or tubes, 42 and 43, it is not possible for the vaned rotors to rotate in the same direction at the same time, as, if the rotors were rotating in the same direction, fluid would be pumped by each in opposite directions through the same channel. It is evident that this could not be accomplished. Therefore, they have to rotate with, and at the Like comsame speed as the differential casing 18 as long as both are subjected to an equal amount of resistance to turning. This would be case if the automobile or power vehicle were proceeding along a straight line on firm ground. However, should the vehicle turn to the right or to the left, the wheel on the outside, turning in a greater radius, would rotate faster, i. e., a greater number of times-than the one on the inside, turning in a smaller radius. Difierential action would then develop in the differential case.

The differential action of the vaned rotors l3 and Hi would cause fluid to flow through the metering channels 42 and 13, from the fluid chamberor port situated on the same side as the wheel turningin the smaller radius, to the one situated on the side of that turning in the greater radius, and vice versa. This circuit of fluid would be created in the following manner.

If the vehicle fitted with a fluid differential was moving in a circle, the driven casing It would rotate at a lesser speed than the rotor situated in the side of the greater radius, but at a greater speed than the one situated on the side of the smaller radius.

Therefore, in relation to the fluid differential case, the vaned rotors would be operating in opposite directions, transmitting to and receiving from each other, an'equal amount of fluid flow. In other words, differential action, as long as it lasts, creates a continual flow of fluid from one fluid chamber to the other and vice versa. The

power that is applied'to the diflerential case [0 the metering tubes 42 and 43 inserted or located between the cams l9. These channels or tubes restrict the volume of fluid passing in a given time, fom one fluid chamber to the other. However, this limited amount of fluid is sufiicient to provide for normal differential action, but insufficient to allow either rotor connected to the wheels, to spin independently. In connection with the metered tubes or channels, any other device may be used that will restrict or interrupt fluid flow from either fluid chamber to the other. 7

Each of the rotors l3 and I4 abuts the cam IS in its respective recess, abutting the central portion ofthe cam but being rotatable past the same, blocking off the annular chamber ll between the fluid chambers 38 and 39, and and 4|, permitting no passage of fluid 'therebetween, the fluid being. diverted into the. fluid chamber 38 or 39 as the case may be, to be pumped by the rotor through the metering tube to the opposite fluid chamber, 40 and 4!. Being restricted passages, these channels 42 and 43 allow but a limited amount of fluid to flow from one fluid chamber to the other, during difierential action.

Differential action takes place by reason of one shaft or axle being retarded in its rotation, either by the turning of the vehicle from a straight line or by one wheel becoming stationary, or nearly so.

In the case of the vehicle turning to right or left, the speed of the driven casing It! remains constant, therefore the vwheel that is turning slower'causes the rotorgin this instanceM; on that side, to act as a pump, and the vanes 20 of this rotor I4 force fluid from the annular 76"chamber I! up and through the fluid chamber 4i- T and into its opposite fluidchamber '39 the rotor I3 through the metering channel 43. This pumping action causes the fluid to create pressure on the vanes .20 of the rotor l3, .or opposite rotor, therefore causing the same to turn faster than the casing l0.

In the case of the rotation of one wheel bee coming almost zero, in this instance, that connected to the rotor M, the driven casing ID still rotates under power at its regular speed, this causing the vanes to force the fluid up through the metering channel 43, as previously described; due to the restricted flow of fluid through the metering channel the rotor of the free wheel does not spin but only rotates at a speed slightly higher than that of the driven casing Hi, thishigher speed being occasioned by the fluid flow from the metering channel acting against the vanes of the rotor I3. An equal metering action is obtained after the fluid has passed through the opposite rotor and is being forced out through the metering channel 43 into the stationary rotor It will be understood that when the vehicle is travelling in a straight line and force is being applied to the casing I0, only one of the metering channels is actually under pressure of the fluid, although no metering action is taking place, the fluid from each rotor remaining under equal pressure.

In connection with the vanes 20:v The vanes are designed for the specific purpose of support ing a load whether moving or stationary while operating in a fluid, and to transmit power by the medium of the same fluid from the differential casing ID in which they rotate to the rotors in which they are set, or vice versa. At the same time they provide differential action of the rotors by transferring from one fluid chamber to another and vice versa, the fluid in which they operate.

When set in place and operating in the fluid the vanes come successively in contact with the cam and are pushed down into their respective slots and spring recesses. By their action the fluid that is contained in the spring recess and vane slots must necessarily be allowed to escape, the grooves 2| providing for this. The notches 22 and 23 provide a channel in which the fluid can circulate in any direction. A volume equal to the space newly occupied by the downward movement of the vane flows up the groove 2! and takes the place of that occupied previously by the vane in the fluid contained in the space above. When the vane has passed the cam, and is pushed out by the compression spring 26, this action is reversed.

The cam I9 connected with each of the rotor recesses is designed to modify the position of the vanes set in the rotor, so that when operating in the fluid medium the vanes will progressively take on or discharge their respective load. These cams are preferably a component part of the differential casing ill, but may be a separate unit. In the persent instance, the wall of the recess is formed to converge or flatten outward slightly off its circular contour.

It is of course understood that modifications and ramifications may be made without in any way departing from the spirit of the. invention as hereinabove described and illustrated.

What I claim is:

1. In a fluid differential, a differential device adapted to provide a compensating action between two driven shafts by transference of vary- 6? ing loads causing variation of internal pressures and comprising a driven casing rotatably mounted in a suitable housing, a pair of like circular recesses located one in either face of said casing, a pair of like circular rotors located one in each of said recesses and being rotatable therein, an annular chamber formed between the circumferential edge of said rotor andt'he inner wall of said recess, a cam portion formed in one section of each of said recesses and being identical one with the other, said cam portion comprising a section of the inner wall of the recess bein flatted out and adapting said rotor in said recess to abut the said cam, a plurality of vanes set in cut-out portions in each of said rotors and being slidable therein, said vanes being rectangular in shape and having a longitudinal slot extending the entire length of the front face of same and provided with notches in the lower end portion, a fluid chamber located on each side of said cam in each of said recesses, said fluid chambers being located in the said casing, a metering channel connecting each of the said fluid chambers with the opposite fluid chamber in the other of said recesses, and said fluid chambers connecting with the said annular chamber in the said recesses, a main reservoir located in said casing between said recesses containing said rotors and having an inlet in the casing leading thereto, a viscous fluid introduced into the said main reservoir and into the said annular chamber in each of said recesses, connecting holes leading from said main reservoir to each inner wall of said recesses, said fluid adapted to flow from the said annular chambers into the said fluid chambers and through said metering channels into the fluid chamber connected thereto, the flow of said fluid being activated by the rotation of said driven casing to act upon said vanes of said rotors to cause said rotors to efiect a pumping action, said metering channels adapted to effect a set fluid control thereby producing correct variation ratio automatically as required.

2. In a fluid diflerential, a cylindrical casing adapted to be power driven to rotate, identical recesses in said casing one on either face of the same in back to back relation, identical cams connected to said recesses, a circular rotor rotatably mounted in each of said recesses and being identical one with the other and abutting the said cam of its respective recess, a plurality of vanes slidably mounted in each of said rotors and having their top ends abutting the inner wall of the recess, said cams being adapted to push said vanes down into their rotor upon the same coming in contact therewith during rotation of the said rotor, a fluid chamber located in said casing on either side of said cam in each of said recesses and leading into an annular chamber formed between .the rotor and the inner wall of its recess, a metered tube connecting each of said fluid chambers on each side of the cam of one recess with the like and opposite fluid chamber in the other of said recesses, a fluid introduced into the said fluid chambers and the annular chamber in each of said recesses and adapted to flow therein through the rotation of said casing and said rotors, said fluid being the medium providing differential action by transferring power from said power driven casing to the said rotors through said vanes of the same, the fluid flow in said casing being controlled by the said metered tubes, a compression spring located in a recess beneath each of said vanes contacts the 7 8 1 vanes to press same upward and maintain it in UNITED STATES PATENTS contact with the inner wall of the recess, and Number Name Date cover plates enclosing the working parts of said 387331 Fischer May 19' 1908 casmg- 1,420,798 Weston June 27, 1922 RODOLPHE VALERY DE LA HITTE. 5 1, 29,1 Ross Sept. 12, 1922 1,887,229 Button Nov. 8, 1932 2,206,907 Loughridge July 9, 1940 REFERENCES CITED 2,229,228 Sutter Jan. 21, 1941 The following references are of record in the ,75 3 Moon May 5 19 5 file 0f thls patenti 10 2,463,091 Dortort, Mar. 11, 1949- 

